Edge tools, for example for woodworking, especially woodturning tools, have to be sharp for obtaining optimum results. Sharpening can be performed by means of a rotating grindstone in a grinding machine. The sharpening is preferably carried out by means of a jig, in which the tool is attached and which is supported by a support bar of the machine. In this way an exact replication of the edge shape and edge angle of a previous sharpening can be obtained.
Hereby, the shape of the edge is exactly the same after each re-sharpening, so that the tool always behaves in the same way at work. With a sharp edge the wood surface becomes finer and may not need sanding or the like.
At re-sharpening of the tool by means of a jig very little steel is removed, and the wear is minimal, prolonging the useful life of a tool.
At a re-sharpening by means of the jig supported by the support bar, a replicated result is only possible with the same jig, with the same protrusion of the tool from the jig, and above all with the same distance between the support bar and the grindstone as at a previous sharpening.
Traditionally, the distance between the support bar and the grindstone has been established by means of a wooden spacer made by the user at the first sharpening of a tool. This is a rather awkward process, also with an inherent risk of then loosing a particular wooden spacer. Different spacers may be needed for different tools. Each spacer will lead to a copying of the edge geometry obtained at a previous sharpening. The precision of the result is depending on the skill and accuracy of the user. Further, the spacer can not be used with a grindstone with another diameter than the original one, if a replicated edge angle is desired.
The main object of the invention is to enable a proper, replicated setting by means of a commercially available device, also with a grindstone of another diameter than of the one previously used.
Another object of the invention is to attain a device for simplifying the setting of the support bar with the highest possible accuracy.